Hello, I’m Nathan, and I’ll be assisting you today. My livelihood depends on your positive feedback, so your satisfaction is my highest priority. Sorry to hear you’re having trouble. The reason this doesn't work is because this is not an option for your phone.You are looking at a manual that is shared with other models, to which that is applicable, but your model does not allow this operation because the rings to answer setting pertains to an internal panasonic answering machine feature. Your model, the 6511, does not have an internal answering system. If you are having an issue with the ring time, it would be in relation to a VOICEMAIL service, which is a feature provided by your phone company, it is not part of the panasonic.So you would either need to dial in to your VM server and listen there for the personal options to adjust that setting OR call the phone company and ask them to adjust it for you on their end.Best regards,Nathan